Photosensitive resin composition, cured product thereof, and printed wiring board

ABSTRACT

Disclosed is a photosensitive resin composition which has excellent concealing properties for appearance defects of a circuit and the like, while having excellent coloring power and resolution that enable the formation of a high-resolution solder resist layer. Specifically disclosed is a photosensitive resin composition which contains a perylene coloring agent, a coloring agent that is in a complementary color relation with the perylene coloring agent, a carboxyl group-containing resin, a compound that contains two or more ethylenically unsaturated groups in each molecule, and a photopolymerization initiator.

TECHNICAL FIELD

The present invention relates to a photosensitive resin composition anda cured product thereof, and a printed wiring board having a solderresist layer composed of the cured product.

BACKGROUND ART

Alkali-developing type photosensitive resin compositions are widely usedas solder resists for printed wiring boards. The solder resists aim atprotecting circuits of printed wiring boards, and the tinting strengththereof is an important property that significantly affects theappearance of printed wiring boards and the concealing property ofcircuits.

Namely, when a solder resist has insufficient tinting strength,contamination and discoloring of a copper circuit formed on a printedwiring board become prominent, which decreases the appearance of theprinted wiring board significantly. Furthermore, a step of mounting,which is a post step in the production of printed wiring boards, hasbeen automated recently, and parts are attached by machines; however, adefect that a solder resist and a copper circuit cannot be recognizedwell during image recognition occurs. This phenomenon is alsoproblematic in AOI (Automatic Optical Inspection) that is a finalinspection of printed wiring boards.

On the other hand, as the photosensitive property of photosolder resiststhat are currently available in the market, general resists have a filmthickness of around 20 μm and resolution property with a line width offrom about 30 μm to 50 μm.

However, although conventional black solder resists are preferable inview of tinting strength (concealing property), they have problems thatthey have an insufficient curing depth and cannot form fine lines sincea black coloring agent having absorbance from the ultraviolet region tothe infrared region has been added thereto. Generally, a carbon blackcoloring agent that is excellent in weather resistance is used as ablack coloring agent; however, since this coloring agent has largeabsorption in the ultraviolet region, when the content thereof is much,it absorbs ultraviolet ray and affects on transmitting property, andthus fine resolution cannot be obtained.

Thus, it was difficult to provide a black photosensitive resincomposition that can form a solder resist layer that simultaneouslysatisfies fine concealing property and high resolution property.

CITATION LIST Patent Literature

-   PLT 1: Japanese Patent Application Laid-Open No. 2008-257045    (Claims)

SUMMARY OF THE INVENTION Technical Problem

The present invention has been developed in view of the above-mentionedbackground art, and aims at providing a photosensitive resin compositionthat is excellent in tinting strength and resolution property, which isexcellent in property of concealing the appearance defect and the likeof a circuit and can form a solder resist layer having high resolutionproperty.

Solution to Problem

The inventors of the present invention have done intensive studies andconsequently found that the above-mentioned problem in resolution inconventional black solder resists is solved and a photosensitive resincomposition having sufficient tinting strength can be obtained, by usinga perylene coloring agent as a coloring agent and a coloring agent thatis in a complementary color relation with the perylene coloring agent incombination, and completed the present invention.

Namely, in an aspect, the present invention is a photosensitive resincomposition comprising a perylene coloring agent, a coloring agent thatis in a complementary color relation with the perylene coloring agent, acarboxyl group-containing resin, a compound having two or moreethylenically unsaturated groups in a molecule, and aphotopolymerization initiator.

In an aspect, in the above-mentioned photosensitive resin composition, adry coating having a thickness of from 18 to 22 μm formed by using thephotosensitive resin composition has a light absorbance of 0.5 or lessat a wavelength of from 400 to 410 nm, and a cured product of the drycoating has an L* value of 40 or less and an a* value and a b* valuethat are each independently in the range of from −5 to 5 in the CIEL*a*b* Color Scale.

Furthermore, in another aspect, the present invention is a dry filmcomprising a coating obtained by applying and drying the above-mentionedphotosensitive resin composition on a film.

Furthermore, in another aspect, the present invention is a cured productobtained by photo-curing a dry coating obtained by applying and dryingthe above-mentioned photosensitive resin composition on a substrate or adry coating obtained by laminating a dry film obtained by applying anddrying the above-mentioned photosensitive resin composition on a film ona substrate, by irradiating with an active energy ray.

Furthermore, in another aspect, the present invention is a printedwiring board having a pattern of a cured product obtained byphoto-curing a dry coating obtained by applying and drying theabove-mentioned photosensitive resin composition on a substrate or a drycoating obtained by laminating a dry film obtained by applying anddrying the above-mentioned photosensitive resin composition on a film ona substrate, by irradiating with an active energy ray.

Advantageous Effects of Invention

The photosensitive resin composition of the present invention havinghigh tinting strength and excellent resolution property has enabledprovision of a solder resist layer that simultaneously satisfies highresolution property and excellent concealing property, which is demandedas a solder resist layer for printed wiring boards for which increasingof circuit thickness and increasing of density have been in progress.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing the a* and b* of the coloring agents.

FIG. 2 is a schematic drawing showing the shapes of the cross-sectionalsurfaces of the patterns formed by the cured coating of thephotosensitive resin composition, of which (A) shows an ideal state inwhich linearity in accordance with a designed width could be obtained inthe depth direction, and (B) shows an undercut state.

DESCRIPTION OF EMBODIMENTS

Hereinafter the embodiments for carrying out the present invention willbe explained in detail.

The photosensitive resin composition of the present embodiment is aphotosensitive resin composition having a black color tone, which ischaracterized by using at least one kind of perylene coloring agent as acoloring agent and at least one kind of coloring agent that is in acomplementary color relation with the perylene coloring agent(hereinafter also referred to as “complementary coloring agent”) incombination, and a solder resist layer formed by using thephotosensitive resin composition of the present embodiment has highresolution property and excellent concealing property.

Specifically, in the photosensitive resin composition of the presentembodiment, the case when a dry coating having a thickness in the rangeof from 18 to 22 μm formed by using the composition has a lightabsorbance of 0.5 or less at any wavelength from 400 to 410 nm ispreferable since finer deep portion-curability can be obtained. Thelight absorbance as used herein is a value obtained by measuring anabsorption spectrum with an ultraviolet-visible spectrometer, and is alogarithm of a light transmittance. For example, a light absorbance of 1corresponds to a transmittance of 10%. This light absorbance is morepreferably from 0.05 to 0.3. When the light absorbance exceeds 0.5,sufficient deep portion-curability may not be obtained, whereas when thelight absorbance is less than 0.05, photo-curing may be insufficient.Furthermore, in order to impart excellent concealing property, it ispreferable to suitably select a combination of at least one kind ofperylene coloring agent and at least one kind of coloring agent that isin a complementary color relation with the perylene coloring agent sothat a light absorbance curve at the visible light region (450 to 800nm) becomes a curve that approximates the light absorbance curve ofcarbon black.

Firstly, the coloring agents included in the photosensitive resincomposition of the present embodiment will be explained.

(Coloring Agent) Perylene Coloring Agent;

A perylene coloring agent imparts, when it is added to a photosensitiveresin composition, high resolution property to a colored photoresist,specifically to a solder resist for printed wiring boards. The presentinvention is a photosensitive resin composition having a black colortone due to mixing of a perylene coloring agent and a complementarycoloring agent, whereas carbon black that has been generally used as ablack coloring agent until now has absorption at the whole wavelengthregions and specifically has high light absorbance at around awavelength of 405 nm, and thus cannot transmit sufficiently a light froma light source to the bottom part of a resist and decreases a curingdepth. On the other hand, a perylene coloring agent has lesserabsorbance at the ultraviolet region as compared to the above-mentionedcarbon black, and thus can improve the resolution property of a solderresist. Since a perylene coloring agent has sufficient tinting strength,it can provide a black photosensitive resin composition that isexcellent in resolution property and tinting strength by being mixedwith a complementary coloring agent and used.

A known perylene coloring agent can be used as the perylene coloringagent that may be used in the present embodiment, and either ofpigments, dyes and colors may be used as long as it is a perylenecoloring agent.

Some perylene coloring agents show colors such as green, yellow, orange,red, purple and black, and examples may include those having thefollowing numbers of the Color Index (C. I.; published by The Society ofDyers and Colourists).

-   Green: Solvent Green 5-   Orange: Solvent Orange 55-   Red: Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190,    194, 224-   Purple: Pigment Violet 29-   Black: Pigment Black 31, 32    Perylene coloring agents other than those mentioned above can also    be used, and for example, Lumogen (registered trademark) Black    FK4280 and Lumogen Black FK4281 manufactured by BASF, which do not    have numbers of the Color Index but are known as near infrared    ray-transmitting black organic pigments; Lumogen F Yellow 083,    Lumogen F Orange 240, Lumogen F Red 305 and Lumogen F Green 850,    which are known as light-collecting fluorescent dyes, and the like    can also be used preferably since they have less absorption in the    ultraviolet region and high tinting strength similarly to the other    perylene compounds.

The incorporation ratio of the perylene coloring agent is preferablyfrom 0.01 to 8 parts by mass, more preferably from 0.05 to 5 parts bymass, with respect to 100 parts by mass of the carboxyl group-containingresin mentioned below, with consideration for tinting property and anamount of absorption of an ultraviolet ray.

(Complementary Coloring Agent)

The complementary coloring agent that is used in combination with theperylene coloring agent in the present embodiment will be explainedbelow. Firstly, the complementary color relation in the presentembodiment will be explained.

Since a coloring agent does not necessarily present a color according tothe Color Index color, the appearance color tone of the photosensitiveresin composition is measured and represented by the method asprescribed in JISZ8729, the a* value and b* value that represent a colorin the L*a*b* Color Scale are confirmed by coordinate axes (see FIG. 1),and a coloring agent for infinitely approximating the (a* value, b*value) of a coating obtained by combination with the perylene coloringagent (0, 0) is selected as a coloring agent in a complementary colorrelation. As used herein, the coating is a cured product of a drycoating in the range of from 15 to 22 μm. Furthermore, as the (a* value,b* value) that infinitely approximate (0, 0), the a* value and b* valueare preferably in the range of from −5 to +5, respectively, and morepreferably in the range of from −2 to +2. Furthermore, the coloringagent that is in a coloring agent in a complementary color relation maybe a perylene coloring agent or a coloring agent other than perylenecoloring agents.

The incorporation ratio in the photosensitive resin composition and themixing ratio with the above-mentioned perylene coloring agent of thecomplementary coloring agent may be suitably selected within the rangein which the color tone of the photosensitive resin composition presentsa black color. As the incorporation ratio of the complementary coloringagent in the photosensitive resin composition, the ratio to the perylenecoloring agent can be set preferably in the range from 0.01 to 8 partsby mass, more preferably from 0.05 to 5 parts by mass, with respect to100 parts by mass of the carboxyl group-containing resin mentionedbelow. The specifics will be mentioned below.

The coloring agent that is in a complementary color relation with theperylene coloring agent as used herein may be any coloring agent (may beeither a pigment, dye or colorant) as long as it can approximate the a*value and b* value in the color scale closer to 0 by the combinationwith the perylene coloring agent, and may include the coloring agentsmentioned below. More preferable combinations with the perylene coloringagent are combinations of Pigment Red 149, 178, 179 with the greenanthraquinone coloring agents mentioned below (Solvent Green 3, SolventGreen 20, Solvent Green 28 and the like), and other examples includecombinations of the perylene coloring agents (Lumogen Black FK4281,Solvent Green 5) with phthalocyanine blue (Pigment Blue 15: 3), andmixed colors (combinations) of perylene coloring agents includingcombinations of red perylene coloring agents (Pigment Red 149, 178, 179)and black perylene coloring agents (Pigment Black 31, 32), andcombinations of black perylene coloring agents (Pigment Black 31, 32)and black perylene coloring agents (Lumogen Black FK4280, 4281).

Blue coloring agents include phthalocyanine and anthraquinone bluecoloring agents, and pigment-based blue coloring agents may includecompounds classified into Pigments, specifically compounds having thenumbers of the Color Index (C. I.; published by The Society of Dyers andColourists) as mentioned below.

Pigment-based blue coloring agents: Pigment Blue 15, 15:1, 15:2, 15:3,15:4, 15:6, 16, 60.

As dye blue coloring agents, Solvent Blue 35, 45, 63, 67, 68, 70, 83,87, 94, 97, 104, 122, 136 and the like can be used. Besides thosementioned above, metal-substituted or unsubstituted phthalocyaninecoloring agents can also be used.

Similarly, green coloring agents include phthalocyanine, anthraquinoneand perylene green coloring agents, and Pigment Green 7, 36, SolventGreen 3, 5, 20, 28 and the like can specifically be used. Besides thosementioned above, metal-substituted or unsubstituted phthalocyaninecoloring agents can also be used.

Yellow coloring agents include anthraquinone, isoindolinone, condensedazo, benzimidazolone, monoazo, disazo yellow coloring agents and thelike, and may specifically include the following ones.

(Anthraquinone Yellow Coloring Agents) Solvent Yellow 163, PigmentYellow 24, 108, 147, 193, 199, 202; (Isoindolinone Yellow ColoringAgents) Pigment Yellow 109, 110, 139, 179, 185; (Condensed Azo YellowColoring Agents) Pigment Yellow 93, 94, 95, 128, 155, 166, 180;(Benzimidazolone Yellow Coloring Agents) Pigment Yellow 120, 151, 154,156, 175, 181; (Monoazo Yellow Coloring Agents) Pigment Yellow 1, 2, 3,4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105,111, 116, 167, 168, 169, 182, 183; (Disazo Yellow Coloring Agents)Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152,170, 172, 174, 176, 188, 198.

Red coloring agents include monoazo, disazo, azo lake, benzimidazolone,diketopyrrolopyrrole, condensed azo, anthraquinone, quinacridone redcoloring agents and the like, and may specifically include the followingones.

(Monoazo Red Coloring Agents) Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12,14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184,187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269; (Disazo RedColoring Agents) Pigment Red 37, 38, 41; (Monoazo Lake Red ColoringAgents) Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1,52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, 68; (Benzimidazolone RedColoring Agents) Pigment Red 171, 175, 176, 185, 208;(Diketopyrrolopyrrole Red Coloring Agents) Pigment Red 254, 255, 264,270, 272; (Condensed Azo Red Coloring Agents) Pigment Red 144, 166, 214,220, 221, 242; (Anthraquinone Red Coloring Agents) Solvent Red 52, 149,150, 207, Pigment Red 168, 177, 216; (Quinacridone Red Coloring Agents)Pigment Red 122, 202, 206, 207, 209.

Other coloring agents of purple, orange, brown, black and the like mayalso be added for the purpose of adjusting the color tone. Specificexamples include Pigment Violet 19, 23, 32, 36, 38, 42, Solvent Violet13, 36, Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46,49, 51, 61, 63, 64, 71, 73, Pigment Brown 23, 25, Pigment Black 1, 7,and the like.

In the present embodiment, it is necessary to adjust the totalincorporation ratio of the coloring agent and the incorporation ratio ofthe perylene coloring agent and complementary coloring agent toproportions sufficient for a solder resist layer composed of theobtained photosensitive resin composition or a cured coating filmthereof to present a black color. To be specific, as mentioned above,the incorporation ratios of the perylene coloring agent andcomplementary coloring agent in the photosensitive resin composition maybe set respectively in the range of preferably from 0.01 to 8 parts bymass, more preferably from 0.05 to 5 parts by mass with respect to 100parts by mass of the carboxyl group-containing resin so that thephotosensitive resin composition or the cured coating film thereofpresents a black color.

In the present embodiment, the black color presented by thephotosensitive resin composition and the cured coating film thereofrefers to a color having such a color tone that an observer recognizesit as a black-based color by observation by the naked eyes. To bespecific, when the appearance color tone of a cured coating film(thickness 18 to 22 μm) of the photosensitive resin composition of thepresent embodiment is measured and represented by the method asprescribed in JISZ8729, it is preferable that the L* value is 40 or lessand the a* value and b* value are each independently in the range offrom −5 to 5 in the CIE L*a*b* Color Scale, although the values dependon a pretreatment of copper. More preferably, the L* value is from 10 to40, and the a* value and b* value that are illimitably closer to 0 aremore preferable.

Although the incorporation ratio of the other coloring agents comprisingthe perylene coloring agent that is in a complementary color relationwith the perylene coloring agent cannot be generalized and may besuitably set since it is affected by the kind of the perylene coloringagent used and the kinds of other additives and the like, for example,the incorporation ratio of the red perylene coloring agent and greenanthraquinone coloring agent, the incorporation ratio of the redperylene coloring agent and black perylene coloring agent (Pigment Black31, 32), and the incorporation ratio of the black perylene coloringagent (Pigment Black 31, 32) and black perylene coloring agent (Lumogen)are preferably in a ratio of from 1:0.01 to 1:20 on the basis of massratio.

Next, the respective constitutional components other than the coloringagents included in the photosensitive resin composition of the presentembodiment will be explained in detail. For the photosensitive resincomposition of the present embodiment, the materials as mentioned belowcan be used.

(Carboxyl Group-Containing Resin)

A carboxyl group-containing resin having a carboxyl group in a moleculeis used for the purpose of imparting alkali developing property in thephotosensitive resin composition of the present embodiment, andconventionally-known various compounds can be used. Specifically, acarboxyl group-containing photosensitive resin having an ethylenicallyunsaturated double bond in a molecule is more preferable from theviewpoints of photo-curing property and developing resistance.Furthermore, the unsaturated double bond is preferably one derived fromacrylic acid or methacrylic acid or a derivative thereof.

Specific examples of the carboxyl group-containing resin are preferablythe compounds listed below.

(1) Carboxyl group-containing resins obtained by copolymerization of(meth)acrylic acid and an unsaturated group-containing substance.(2) Carboxyl group-containing urethane resins obtained by an additionpolymerization reaction between a diisocyanate, a carboxylicacid-containing dialcohol compound and a diol compound.(3) Photosensitive carboxyl group-containing urethane resins obtained byan addition polymerization reaction of a diisocyanate, a bifunctionalepoxy(meth)acrylate or a partial acid anhydride-modified productthereof, a carboxylic acid-containing dialcohol compound and a diolcompound.(4) Terminal (meth)acrylated carboxyl group-containing urethane resinsobtained by adding a compound having one hydroxyl group and one or more(meth)acryl group in a molecule during the synthesis of the resins ofthe above-mentioned (2) and (3).(5) Terminal (meth)acrylated carboxyl group-containing urethane resinsobtained by adding a compound having one isocyanate group and one ormore (meth)acryl group in a molecule during the synthesis of the resinsof the above-mentioned (2) and (3).(6) Photosensitive carboxyl group-containing resins obtained by reacting(meth)acrylic acid with a bifunctional and multifunctional (solid) epoxyresins to add a dibasic acid anhydride to the hydroxyl groups present onthe side chains.(7) Photosensitive carboxyl group-containing resins obtained by reacting(meth)acrylic acid with a multifunctional epoxy resin obtained byfurther epoxylating the hydroxyl groups of a bifunctional (solid) epoxyresin with epichlorohydrin and adding a dibasic acid anhydride to thegenerated hydroxyl groups.(8) Carboxyl group-containing polyester resins obtained by reacting abifunctional oxetane resin with a dicarboxylic acid, and adding adibasic acid anhydride to the generated primary hydroxyl groups.(9) Photosensitive carboxyl group-containing resin obtained by furtheradding a compound having one epoxy group and one or more (meth)acrylgroup in a molecule to the above-mentioned resins.

In the present specification, the (meth)acrylate is a generic term usedto refer to acrylates, methacrylates and mixtures thereof, and the sameapplies to other similar expressions.

Since the carboxyl group-containing resin as mentioned above has manyfree carboxyl groups on the side chains of the backbone polymer, itenables developing with an alkali aqueous solution.

Furthermore, the above-mentioned carboxyl group-containing resinpreferably has an acid value in the range of from 40 to 200 mg KOH/g.When the acid value is less than 40 mg KOH/g, it becomes difficult todevelop with an alkali, whereas when the acid value exceeds 200 mgKOH/g, dissolution of an exposed part by a developer proceeds and linesget thin more than necessary, and in some cases, an exposed part and anunexposed part are dissolved by a developer and peeled off withoutdistinction and thus drawing of a normal resist pattern becomesdifficult. More preferably, the acid value is in the range of from 45 to120 mg KOH/g.

Furthermore, although the weight average molecular weight of theabove-mentioned carboxyl group-containing resin differs depending on theresin backbone, it is generally preferably in the range of from 2,000 to150,000. When the weight average molecular weight is less than 2,000,tack free performance become poor in some cases, the humidity resistanceof a coating after exposure becomes worse, and film thickness lossoccurs during developing and resolution is deteriorated significantly insome cases. On the other hand, when the weight average molecular weightexceeds 150,000, developing property becomes worse significantly, andstorage stability is deteriorated in some cases. More preferably, theweight average molecular weight is in the range of from 5,000 to100,000.

The incorporation ratio of such carboxyl group-containing resin ispreferably from 20 to 60 mass % in the whole composition. In the casewhen the incorporation ratio is less than 20 mass %, coating strength isdecreased in some cases. On the other hand, in the case when theincorporation ratio is more than 60 mass %, viscosity is increased, orapplication property and the like are decreased. More preferably, theincorporation ratio is from 30 to 50 mass %.

These carboxyl group-containing resins can be used without being limitedto those mentioned above, and they can be used by one kind or by mixingplural kinds.

(Photopolymerization Initiator)

The photosensitive resin composition of the present embodiment comprisesa photopolymerization initiator.

As the photopolymerization initiator, it is preferable to use one ormore kind selected from the group consisting of oxime esterpolymerization initiators, α-aminoacetophenone photopolymerizationinitiators and acylphosphineoxide photopolymerization initiators.

Examples of the oxime ester photopolymerization initiators may includecommercial products such as CGI-325, IRGACURE OXE01 and IRGACURE OXE02manufactured by Ciba Japan, N-1919 and ADEKA ARKLS NCI-831 manufacturedby ADEKA, and TOE Series manufactured by Nippon Chemical Works Co., Ltd.

Specific α-aminoacetophenone photopolymerization initiators may include2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone,N,N-dimethylaminoacetophenone and the like. Examples of commercialproducts may include IRGACURE 907, IRGACURE 369 and IRGACURE 379manufactured by Ciba Japan, and the like.

Examples of the acylphosphineoxide photopolymerization initiators mayinclude 2,4,6-trimethylbenzoyldiphenylphosphineoxide,bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphineoxide and thelike. Examples of commercial products may include LUCIRIN TPOmanufactured by BASF, IRGACURE 819 manufactured by Ciba Japan, and thelike.

The incorporation ratio of such photopolymerization initiators ispreferably from 0.01 to 30 parts by mass with respect to 100 parts bymass of the carboxyl group-containing resin. When the incorporationratio is less than 0.01 parts by mass, photo-curing property on copperbecomes insufficient, which leads to peeling of a coating anddeterioration of coating properties such as chemical resistance. On theother hand, when the incorporation ratio exceeds 30 parts by mass, thelight absorbance of the photopolymerization initiator on the surface ofa solder resist coating becomes intense, and deep portion-curabilitytends to decrease. More preferably, the incorporation ratio is from 0.5to 15 parts by mass.

In addition, in the cases of the oxime ester photopolymerizationinitiators, the incorporation ratio thereof is preferably from 0.01 to20 parts by mass with respect to 100 parts by mass of the carboxylgroup-containing resin. More preferably, the incorporation ratio is inthe range from 0.01 to 5 parts by mass.

Furthermore, a photopolymerization initiator other than the compoundsmentioned above, a light polymerization-initiation aid and a sensitizercan be used for the photosensitive resin composition of the presentembodiment, and examples may include benzoin compounds, acetophenonecompounds, anthraquinone compounds, thioxanthone compounds, ketalcompounds, benzophenone compounds, xanthone compounds, titanocenecompounds and tertiary amine compounds, and the like.

Specific examples of the benzoin compounds include benzoin, benzoinmethyl ether, benzoin ethyl ether and benzoin isopropyl ether.

Specific examples of the acetophenone compounds include acetophenone,

-   2,2-dimethoxy-2-phenylacetophenone,-   2,2-diethoxy-2-phenylacetophenone and-   1,1-dichloroacetophenone.

Specific examples of the anthraquinone compounds include2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone and1-chloroanthraquinone.

Specific examples of the thioxanthone compounds include2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthoneand 2,4-diisopropylthioxanthone.

Specific examples of the ketal compounds include acetophenone dimethylketal, benzyl dimethyl ketal and the like.

Specific examples of the benzophenone compounds include benzophenone,4-benzoyldiphenylsulfide, 4-benzoyl-4′-methyldiphenylsulfide,4-benzoyl-4′-ethyldiphenylsulfide and4-benzoyl-4′-propyldiphenylsulfide.

Specific examples of the titanocene compounds includebis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium.

Specific examples of the tertiary amine compounds include ethanolaminecompounds, compounds having a dialkylaminobenzene structure such asdialkylaminobenzophenones such as 4,4′-dimethylaminobenzophenone(NISSOCURE MABP manufactured by Nippon Soda Co., Ltd.) and4,4′-diethylaminobenzophenone (EAB manufactured by Hodogaya ChemicalCo., Ltd.), dialkylamino group-containing coumarin compounds such as7-(diethylamino)-4-methyl-2H-1-benzopyran-2-one(7-(diethylamino)-4-methylcoumarin), ethyl 4-dimethylamino benzoate(KAYACURE EPA manufactured by Nippon Kayaku Co., Ltd.), ethyl2-dimethylamino benzoate (Quantacure DMB manufactured by InternationalBio-Synthetics Inc.), (n-butoxy)ethyl 4-dimethylamino benzoate(Quantacure BEA manufactured by International Bio-Synthetics Inc.),p-dimethylaminobenzoic acid isoamyl ethyl ester (KAYACURE DMBImanufactured by Nippon Kayaku Co., Ltd.) and 2-ethylhexyl4-dimethylamino benzoate (Esolol507 manufactured by VanDyk).

Among these, thioxanthone compounds and tertiary amine compounds arepreferable. It is preferable to incorporate a thioxanthone compound inview of deep portion-curability.

The incorporation ratio of such thioxanthone compound is preferably 20parts by mass or less with respect to 100 parts by mass of the carboxylgroup-containing resin. When the incorporation ratio of the thioxanthonecompound is too much, thick film curability is deteriorated, which leadsto increase in the costs for products. More preferably, theincorporation ratio is 10 parts by mass or less.

As the tertiary amine compounds, compounds having a dialkylaminobenzenestructure are preferable, of which dialkylaminobenzophenone compounds,and dialkylamino group-containing coumarin compounds having the maximumabsorb wavelength at from 350 to 410 nm are specifically preferable.

Among the dialkylaminobenzophenone compounds,4,4′-diethylaminobenzophenone is preferable since it has low toxicity.Since the dialkylamino group-containing coumarin compounds having themaximum absorb wavelength at from 350 to 410 nm have the maximum absorbwavelength at the ultraviolet area, they provides little coloring, andthus it becomes possible to obtain a colorless and transparentphotosensitive composition as well as a colored solder resist film usinga coloring agent, which reflects the color of the coloring agent itself.Specifically, 7-(diethylamino)-4-methyl-2H-1-benzopyran-2-one ispreferable since it shows an excellent sensitizing effect against laserlight at a wavelength of from 400 to 410 nm.

The incorporation ratio of such tertiary amine compound is preferablyfrom 0.1 to 20 parts by mass with respect to 100 parts by mass of thecarboxyl group-containing resin. When the incorporation ratio is lessthan 0.1 part by mass, a sufficient sensitizing effect tends to beunable to be obtained. On the other hand, when the incorporation ratioexceeds 20 parts by mass, light absorption by the tertiary aminecompound on the surface of a dry solder resist coating becomes intenseand deep portion-curability tends to decrease. More preferably, theincorporation ratio is from 0.1 to 10 parts by mass.

These photopolymerization initiators, light-initiation aids andsensitizers can be used solely or as a mixture of two or more kinds.

(Compound Having Two or More Ethylenically Unsaturated Groups inMolecule)

The photosensitive resin composition of the present embodiment comprisesa compound having two or more ethylenically unsaturated groups in amolecule.

The compound having two or more ethylenically unsaturated groups in amolecule is photo-cured by irradiation with active energy ray toinsolubilize the carboxyl group-containing resin in an aqueous alkalisolution or help the insolubilization.

Examples of such compound may include diacrylates of glycols such asethylene glycol, methoxytetraethylene glycol, polyethylene glycol andpropylene glycol; polyvalent acrylates of polyvalent alcohols such ashexanediol, trimethylolpropane, pentaerythritol and dipentaerythritoland tris-hydroxyethylisocyanurate and ethylene oxide additives orpropylene oxide additives thereof; polyvalent acrylates ofphenoxyacrylate, bisphenol A diacrylate and ethylene oxide additives orpropylene oxide additives of these phenols; polyvalent acrylates ofglycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidylether, trimethylolpropane triglycidyl ether and triglycidylisocyanurate; and melamine acrylates and/or respective methacrylatesthat correspond to the above-mentioned acrylates; and the like.

Furthermore, examples may include epoxy acrylate resins obtained byreacting a multifunctional epoxy resin such as a cresol-novolak typeepoxy resin with acrylic acid, epoxyurethane acrylate compounds obtainedby further reacting the hydroxyl groups of the epoxy acrylate resinswith a half-urethane compound of a hydroxyacrylate such aspentaerythritol triacrylate and isophorone diisocyanate. Such epoxyacrylate resins can improve photo-curability without decreasing touchdryness of fingers.

The incorporation ratio of such compound having two or moreethylenically unsaturated groups in a molecule is preferably from 5 to100 parts by mass with respect to 100 parts by mass of the carboxylgroup-containing resin. In the case when the incorporation ratio is lessthan 5 parts by mass, photo-curability is decreased, and formation of apattern becomes difficult by alkali developing after irradiation with anactive energy ray. On the other hand, in the case when the incorporationratio exceeds 100 parts by mass, solubility against an alkali aqueoussolution is decreased, and a coating becomes brittle. More preferably,the incorporation ratio is from 1 to 70 parts by mass.

(Thermosetting Component)

A thermosetting component can be added to the photosensitive resincomposition of the present embodiment so as to impart heat resistance. Athermosetting component having two or more cyclic ether groups and/orcyclic thioether groups (hereinafter abbreviated as “cyclic (thio)ethergroups”) in a molecule is specifically preferable.

Such thermosetting component having two or more cyclic (thio)ethergroups in a molecule is preferably a compound having two or more ofeither one or both of 3, 4 or 5-membered cyclic ether groups or cyclicthioether groups in a molecule, and examples may include compoundshaving at least two or more epoxy groups in a molecule, i.e.,multifunctional epoxy compounds, compounds having at least two or moreoxetanyl groups in a molecule, i.e., multifunctional oxetane compounds,compounds having two or more cyclic thioether groups in a molecule,i.e., episulfide compounds, and the like.

Examples of the multifunctional epoxy compounds may include, but are notlimited to, bisphenol A type epoxy resins such as jER828, jER834,jER1001 and jER1004 manufactured by Japan Epoxy Resins Co., Ltd.,EPICLON 840, EPICLON 850, EPICLON 1050 and EPICLON 2055 manufactured byDIC, EPOTOHTO YD-011, EPOTOHTO YD-013, EPOTOHTO YD-127 and EPOTOHTOYD-128 manufactured by Tohto Kasei Co., Ltd., D. E. R. 317, D. E. R.331, D. E. R. 661 and D. E. R. 664 manufactured by Dow Chemical Company,ARALDIDE 6071, ARALDIDE 6084, ARALDIDE GY250 and ARALDIDE GY260manufactured by Ciba Japan, SUMI-EPDXY ESA-011, SUMI-EPDXY ESA-014,SUMI-EPDXY ELA-115 and SUMI-EPDXY ELA-128 manufactured by SumitomoChemical Co., Ltd., and A. E. R. 330, A. E. R. 331, A. E. R. 661 and A.E. R. 664 manufactured by Asahi Kasei Corporation (all are trade names);brominated epoxy resins such as jERYL903 manufactured by Japan EpoxyResins Co., Ltd., EPICLON 152 and EPICLON 165 manufactured by DIC,EPOTOHTO YDB-400 and EPOTOHTO YDB-500 manufactured by Tohto Kasei Co.,Ltd., D. E. R. 542 manufactured by Dow Chemical Company, ARALDIDE 8011manufactured by Ciba Japan, SUMI-EPDXY ESB-400 and SUMI-EPDXY ESB-700manufactured by Sumitomo Chemical Co., Ltd., and A. E. R. 711 and A. E.R. 714 manufactured by Asahi Kasei Corporation (all are trade names);novolak type epoxy resins such as jER152 and jER154 manufactured byJapan Epoxy Resins Co., Ltd., D. E. N. 431 and D. E. N. 438 manufacturedby Dow Chemical Company, EPICLON N-730, EPICLON N-770 and EPICLON N-865manufactured by DIC, EPOTOHTO YDCN-701 and EPOTOHTO YDCN-704manufactured by Tohto Kasei Co., Ltd., ARALDIDE ECN1235, ARALDIDEECN1273, ARALDIDE ECN1299 and ARALDIDE XPY307 manufactured by CibaJapan, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S and RE-306 manufacturedby Nippon Kayaku Co., Ltd., SUMI-EPDXY ESCN-195× and SUMI-EPDXY ESCN-220manufactured by Sumitomo Chemical Co., Ltd., and A. E. R. ECN-235 and A.E. R. ECN-299 manufactured by Asahi Kasei Corporation (all are tradenames); bisphenol F type epoxy resins such as EPICLON 830 manufacturedby DIC, jER807 manufactured by Japan Epoxy Resins Co., Ltd., EPOTOHTOYDF-170, EPOTOHTO YDF-175 and EPOTOHTO YDF-2004 manufactured by TohtoKasei Co., Ltd., and ARALDIDE XPY306 manufactured by Ciba Japan (all aretrade names); hydrogenated bisphenol A type epoxy resins such asEPOTOHTO ST-2004, EPOTOHTO ST-2007 and EPOTOHTO ST-3000 manufactured byTohto Kasei Co., Ltd. (trade names); glycidylamine type epoxy resinssuch as jER604 manufactured by Japan Epoxy Resins Co., Ltd., EPOTOHTOYH-434 manufactured by Tohto Kasei Co., Ltd., ARALDIDE MY720manufactured by Ciba Japan and SUMI-EPDXY ELM-120 manufactured bySumitomo Chemical Co., Ltd. (all are trade names); hydantoin type epoxyresins such as ARALDIDE CY-350 manufactured by Ciba Japan (trade name);alicyclic epoxy resins such as CELOXIDE 2021 manufactured by DaicelCorporation, and ARALDIDE CY175 and ARALDIDE CY179 manufactured by CibaJapan (all are trade names); trihydroxyphenylmethane type epoxy resinssuch as YL-933 manufactured by Japan Epoxy Resins Co., Ltd., and T. E.N., EPPN-501 and EPPN-502 manufactured by Dow Chemical Company (all aretrade names); bixylenol type or biphenol type epoxy resins such asYL-6056, YX-4000 and YL-6121 manufactured by Japan Epoxy Resins Co.,Ltd. (all are trade names) or mixtures thereof; bisphenol S type epoxyresins such as EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30manufactured by Asahi Denka Co., Ltd., and EXA-1514 manufactured by DIC(trade names); bisphenol A novolak type epoxy resins such as jER157Smanufactured by Japan Epoxy Resins Co., Ltd.; tetraphenylol ethane typeepoxy resins such as jERYL-931 manufactured by Japan Epoxy Resins Co.,Ltd. and ARALDIDE 163 manufactured by Ciba Japan (all are trade names);heterocyclic epoxy resins such as ARALDIDE PT810 manufactured by CibaJapan and TEPIC manufactured by Nissan Chemical Industries, Ltd. (allare trade names); diglycidyl phthalate resins such as BLENMER DGTmanufactured by NOF Corporation; tetraglycidylxylenoylethane resins suchas ZX-1063 manufactured by Tohto Kasei Co., Ltd.; naphthalenegroup-containing epoxy resins such as ESN-190 and ESN-360 manufacturedby Nippon Steel Chemical Co., Ltd., and HP-4032, EXA-4750 and EXA-4700manufactured by DIC; epoxy resins having a dicyclopentadiene backbonesuch as HP-7200 and HP-7200H manufactured by DIC; glycidylmethacrylate-copolymerized epoxy resins such as CP-50S and CP-50Mmanufactured by NOF Corporation; as well as copolymerized epoxy resinsof cyclohexylmaleimide and glycidyl methacrylate; epoxy-modifiedpolybutadiene rubber derivatives (for example, PB-3600 manufactured byDaicel Corporation, and the like), CTBN-modified epoxy resins (forexample, YR-102 and YR-450 manufactured by Tohto Kasei Co., Ltd., andthe like), and the like. These epoxy resins can be used solely or as acombination of two or more kinds.

Examples of the multifunctional oxetane compounds may includemultifunctional oxetanes such as bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether,1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene,1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene,(3-methyl-3-oxetanyl)methyl acrylate, (3-ethyl-3-oxetanyl)methylacrylate, (3-methyl-3-oxetanyl)methyl methacrylate,(3-ethyl-3-oxetanyl)methyl methacrylate and oligomers or copolymersthereof, and etherificated products of oxetane alcohol and novolakresins, poly(p-hydroxystyrene), Cardo type bisphenols, calixarenes,calixresorcinarenes or resins having hydroxyl groups such assilsesquioxane, and the like. Furthermore, copolymers of an unsaturatedmonomer having an oxetane ring and an alkyl(meth)acrylate may also beincluded.

Examples of the multifunctional episulfide resins may include YL7000(bisphenol A type episulfide resin) manufactured by Japan Epoxy ResinsCo., Ltd., and the like. Furthermore, an episulfide resin obtained byreplacing the oxygen atom in the epoxy group of a novolak type epoxyresin with a sulfur atom by using a similar synthesis method, and thelike can also be used.

The incorporation ratio of the thermosetting component having two ormore cyclic (thio)ether groups in a molecule is preferably in the rangefrom 0.6 to 2.5 equivalent amount with respect to 1 equivalent amount ofthe carboxyl group of the carboxyl group-containing resin. In the casewhen the incorporation ratio is less than 0.6 equivalent amount, thecarboxyl groups remain in a solder resist film, thereby heat resistance,alkali resistance, electrical insulating property and the like aredecreased. On the other hand, in the case when the incorporation ratioexceeds 2.5 equivalent amount, cyclic (thio)ether groups having a lowmolecular weight remain in a dry coating, thereby the strength and thelike of the coating are decreased. More preferably, the incorporationratio is in the range of from 0.8 to 2.0 equivalent amount.

In the case when the above-mentioned thermosetting component having twoor more cyclic (thio)ether groups in a molecule is used in thephotosensitive resin composition of the present embodiment, it ispreferable to incorporate a thermosetting catalyst. Examples of suchthermosetting catalyst may include imidazole derivatives such asimidazole, 2-methylimidazole, 2-ethylimidazole,2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole,1-cyanoethyl-2-phenylimidazole and1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such asdicyandiamide, benzyldimethylamine,4-(dimethylamino)-N,N-dimethylbenzylamine,4-methoxy-N,N-dimethylbenzylamine and 4-methyl-N,N-dimethylbenzylamine,hydrazine compounds such as adipic acid dihydrazide and sebacic aciddihydrazide; phosphorus compounds such as triphenylphosphine, and thelike. Furthermore, examples of commercial products may include 2MZ-A,2MZ-OK, 2PHZ, 2P4BHZ and 2P4 MHZ manufactured by Shikoku ChemicalCorporation (all are trade names of imidazole compounds), U-CAT(registered trademark) 3503N and U-CAT3502T manufactured by San-AproLtd. (all are trade names of block isocyanate compounds ofdimethylamine), DBU, DBN, U-CATSA102 and U-CAT5002 (all are bicyclicamidine compounds and salts thereof), and the like. Specifically, thethermosetting catalysts are not limited to these and may bethermosetting catalysts of epoxy resins or oxetane compounds, or thosepromoting the reaction between epoxy groups and/or oxetanyl groups andcarboxyl groups, and may be used solely or as a mixture of two or morekinds. Furthermore, guanamine, acetoguanamine, benzoguanamine, melamine,and S-triazine derivatives such as2,4-diamino-6-methacryloyloxyethyl-S-triazine,2-vinyl-2,4-diamino-5-triazine,2-vinyl-4,6-diamino-5-triazine-isocyanuric acid additive and2,4-diamino-6-methacryloyloxyethyl-S-triazine-isocyanuric acid additivecan also be used, and it is preferable to use these compounds that alsoact as adhesion-imparting agents and the above-mentioned thermosettingcatalyst in combination.

The incorporation ratio of these thermosetting catalysts is sufficientat a general quantitative ratio, and for example, it is preferably from0.1 to 20 parts by mass, more preferably from 0.5 to 15.0 parts by masswith respect to 100 parts by mass of the carboxyl group-containing resinor the thermosetting component having two or more cyclic (thio)ethergroups in a molecule.

A filler can be incorporated in the photosensitive resin composition ofthe present embodiment as necessary so as to increase the physicalstrength and the like of a coating thereof. As such filler, knowninorganic or organic fillers can be used, and specifically, bariumsulfate, spherical silica and talc are preferably used. Furthermore,metal hydroxides such as titanium oxide, metal oxides and aluminumhydroxide can also be used as body pigment fillers. The incorporationratio of these fillers is preferably 75 mass % or less of the wholeamount of the composition. In the case when the incorporation ratioexceeds 75 mass % of the whole amount of the composition, the viscosityof an insulating composition is increased, thereby application andmolding properties are decreased, and a cured product becomes brittle.More preferably, the incorporation ratio is a ratio from 0.1 to 60 mass%.

Furthermore, an organic solvent can be used for the photosensitive resincomposition of the present embodiment for synthesizing theabove-mentioned carboxyl group-containing resin or preparing thecomposition, or for adjusting the viscosity for applying to a substrateor carrier film.

Examples of such organic solvent may include ketones, aromatichydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols,aliphatic hydrocarbons, petroleum solvents and the like. Morespecifically, the examples include ketones such as methyl ethyl ketoneand cyclohexanone; aromatic hydrocarbons such as toluene, xylene andtetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve,butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propyleneglycol monomethyl ether, dipropylene glycol monomethyl ether,dipropylene glycol diethyl ether and triethylene glycol monoethyl ether;esters such as ethyl acetate, butyl acetate, dipropylene glycol methylether acetate, propylene glycol methylether acetate, propylene glycolethyl ether acetate, propylene glycol butyl ether acetate, methyllactate and ethyl lactate butyl lactate; alcohols such as ethanol,propanol, ethylene glycol and propylene glycol; aliphatic hydrocarbonssuch as octane and decane; petroleum solvents such as petroleum ether,petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha;and the like. Such organic solvents are used solely or as a mixture oftwo or more kinds.

The photosensitive resin composition of the present embodiment canfurther include as necessary known additives such as known heatpolymerization inhibitors such as hydroquinone, hydroquinone methylether, t-butylcatechol, pyrogallol and phenotiazine, known thickeningagents such as micropowder silica, organic bentonite andmontmorillonite, defoaming agents such as silicone, fluorine and polymerdefoaming agents and/or leveling agents, antioxidants andanticorrosives.

EXAMPLES

Hereinafter the present embodiment will be explained with referring toExamples and Comparative Examples, but it is needless to say that thepresent invention is not limited by the following Examples. In addition,unless otherwise indicated, the “part(s)” represents “part(s) by mass”in all of the following cases.

<Carboxyl Group-Containing Resin>

220 parts of a cresol novolak type epoxy resin (“EPICLON N-695”manufactured by DIC, epoxy equivalent amount: 220) was put into afour-necked flask equipped with a stirrer and a reflux condenser, and214 parts of carbitol acetate was added thereto and dissolved byheating. Next, 0.46 part of hydroquinone as a polymerization inhibitorand 1.38 parts of triphenylphosphine as a reaction catalyst were added.This mixture was heated to from 95 to 105° C., 72 parts of acrylic acidwas gradually added dropwise, and the mixture was reacted for 16 hours.This reaction product was cooled to from 80 to 90° C., 106 parts oftetrahydrophthalic acid anhydride was added, the mixture was reacted for8 hours and cooled, and the reaction solution (this is referred to as“varnish”) was then taken out. The carboxyl group-containing resinobtained by such way had an acid value of a solid of 100 mg KOH/g and anonvolatile content of 65%.

Compounding Example

The following components were pre-mixed in a stirrer at the followingincorporation amounts and kneaded in a triple roll mill, therebyrespective photosensitive resin compositions for solder resists(Examples 1 to 6 and Comparative Examples 1 to 4) were prepared. Inaddition, the dispersion degrees of the obtained photosensitive resincompositions were evaluated by particle size measurement by using agrindometer manufactured by Eriksen and were found to be 15 μm or less.

TABLE 1 Composition Examples Comparative Examples (Parts by mass) 1 2 34 5 6 1 2 3 4 Colorants Perylene *1 1 2 1 2 Colorants *2 3 1 3 *3 0.8 43 *4 0.5 0.5 0.5 3 Anthraquinone 2 colorant *5 Phthalocyanine 1.5 1 blue*6 Carbon Black *7 1.5 0.7 Varnish 154 154 154 154 154 154 154 154 154154 Photopolymerization *8 10 10 10 10 2 10 10 10 10 10 initiators *9 11 1 1 1 1 1 1 1 *10  1 Thermosetting resin *11  20 20 20 20 20 20 20 2020 20 *12  30 30 30 30 30 30 30 30 30 30 DPHA *13 20 20 20 20 20 20 2020 20 20 Dicyandiamide *14 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3Barium sulfate *15 100 100 100 100 100 100 100 100 100 100 Orgnicbentonite *16 10 10 10 10 10 10 10 10 10 10 Silicone defoaming agent *173 3 3 3 3 3 3 3 3 3 Organic solvent *18 20 20 20 20 20 20 20 20 20 20[Notes] *1: Pigment Red 149 *2: Pigment Black 31 *3: Lumogen BlackFK4281 *4: Solvent Green 5 *5: Solvent Green 3 *6: Pigment Blue 15:3 *7:Pigment Black 7 *8:2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one(manufactured by Ciba Japan; IRGACURE 369) *9:Bis(η5-cyclopentadienyl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium (manufactured by Ciba Japan; IRGACURE 784) *10: Oxime esterphotopolymerization initiator (manufactured by ADEKA: ADEKA ARKLSNCI-831) *11: Phenol novolak type epoxy resin (manufactured by DowChemical Company; DEN-431) *12: Bixylenol type epoxy resin (manufacturedby Japan Epoxy Resins Co., Ltd.; YX-4000) *13: Dipentaerythritolhexaacrylate (manufactured by Nippon Kayaku Co., Ltd.; DPHA) *14:Dicyandiamide (manufactured by Japan Epoxy Resins Co., Ltd.) *15: Bariumsulfate (manufactured by Sakai Chemical Industries Co., Ltd.; B30) *16:Organic bentonite (manufactured by Elementis Japan) *17: Siliconedefoaming agent (manufactured by Shin-Etsu Chemical Co., Ltd.) *18:Dipropylene glycol monomethyl ether (manufactured by Dow ChemicalCompany Japan; DPM)

Evaluation of Solder Resist Performance: (Method for Preparing Substratefor Evaluation)

The photosensitive resin compositions of Examples 1 to 6 and ComparativeExamples 1 to 4 obtained as above were each applied to the whole surfaceof a patterned copper foil substrate, dried at 80° C. for 30 minutes,and allowed to cool to room temperature. A solder resist pattern wasexposed on this substrate at the optimum exposure amount by using anexposing device comprising a metal halide lamp mounted thereon(manufactured by Orc Manufacturing Co., Ltd.), and developed by using30° C. of a 1 wt % aqueous sodium carbonate solution under a conditionof a spraying pressure of 0.2 MPa for 60 seconds to give a resistpattern. This substrate was cured by heating at 150° C. for 60 minutes.The following properties were evaluated on the obtained printedsubstrate (substrate for evaluation).

<Color Tone and L*a*b* Values>

The cured coatings of the photosensitive resin compositions of Examples1 to 6 and Comparative Examples 1 to 4 were prepared according to theabove-mentioned method for the preparation of the substrate forevaluation. The film thickness was prepared so that the film thicknessafter drying became 20±2 μm. The color of the obtained cured coating wasmeasured by using a spectrophotometer. CM-2600d manufactured by KONICAMINOLTA was used as the spectrophotometer, and the CIE L*a*b* was usedas a color scale. The value obtained by measuring by an SCI mode on ahomogeneous coating surface on a copper foil substrate was defined as acolor value. The result of the evaluation is shown in Table 2.

<Optimal Exposure Amount>

A copper clad laminate substrate is polished by using a buffing roll,washed with water and dried, and the photosensitive resin compositionsof Examples 1 to 6 and Comparative Examples 1 to 4 are each appliedthereto by a screen printing process and dried in a hot air circulationdrying oven at 80° C. for 30 minutes. After the drying, the substratewas exposed via a photomask (Step Tablet No. 2 manufactured by EastmanKodak) by using an exposure machine comprising a metal halide lampmounted thereon (manufactured by Orc Manufacturing Co., Ltd.). Theirradiated product as a test piece was developed by using a developer (a1 wt % aqueous sodium carbonate solution) at a spraying pressure of 2kg/cm² for 60 seconds, and the number of layers of the remaining coatingwas determined by visual observation. The exposure amount at which thenumber of layers of the remaining coating became 6 was used as asuitable exposure amount. The result of the evaluation is shown in Table2.

<Resolution Property and Cross-Sectional Surface Shape of Line>

A substrate obtained by forming a circuit pattern with line/space of300/300 on a copper clad laminate board having a copper thickness of 35μm, which was polished by a buffing roll as a pretreatment, washed withwater and dried, was used as a substrate. The photosensitive resincompositions of Examples 1 to 6 and Comparative Examples 1 to 4 wereeach applied to the above-mentioned pretreated substrate by a screenprinting process, and dried in a hot air circulation drying oven at 80°C. for 30 minutes. After the drying, the substrate was exposed by usinga high-pressure mercury lamp exposure device. As an exposure pattern, apattern in which lines of 30/40/50/60/70/80/90/100 μm are drawn in aspace portion was used. The exposure amount was an exposure amountobtained by evaluating the optimal exposure amount. After the exposure,the substrate was developed by using a 1 wt % aqueous sodium carbonatesolution of 30° C. at a spraying pressure of 0.2 MPa for 60 seconds toform a pattern, and the width of the remaining minimum line was used asresolution property.

Furthermore, the substrate was cured by heating at 150° C. for 60minutes to give a cured coating, and the cross-sectional surface of theline part of the cured coating at a designed value of 100 μm wasobserved. This cross-sectional surface shape was evaluated by roughlyclassifying as shown in the schematic drawings described in FIG. 2. FIG.2 shows schematic drawings in the cases when the following phenomenaoccur. Specifically, in the case of the evaluation ◯, declination fromthe designed value was within 5 μm at both the upper and lower parts ofthe line. The evaluation x means a degree at which undercut occurs andthe solder resist can be used but has room for improvement. The resultis shown in Table 2.

◯; An ideal state in which linearity in accordance with a designed widthcan be obtained in the depth direction (see FIG. 2(A))

x; An undercut state (see FIG. 2(B))

<Light Absorbance>

The photosensitive resin compositions of Examples 1 to 6 and ComparativeExamples 1 to 4 were each applied to the whole surface of a glass plateso as to became 20±2 μm as a dry coating, dried at 80° C. for 30minutes, and allowed to cool to room temperature. This glass substratewas set on an ultraviolet-visible spectrometer, an absorption spectrumat the 405±5 nm part was measured, and a light absorbance at 405 nm wascalculated.

TABLE 2 Examples Comparative Examples Evaluation 1 2 3 4 5 6 1 2 3 4Color tone Black Black Black Black Black Black Green Purple- BlackOrange black L* 33 33 31 32 33 29 41 32 27 50 a* −1 −0.9 −2 0.8 −0.9 0.1−6 7 0.3 15 b* 3 2 5 1.5 2 −1 6 −1 0.4 25 Absorbance 0.3 0.3 0.3 0.3 0.30.3 0.2 0.3 1.1 0.3 (405 nm) Optimal exposure 300 300 300 300 100 300200 300 500 300 amount On resist (mJ/cm²) Resolution property 30 30 3030 30 30 30 30 50 30 (μm) Shape of ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ X ◯ cross-sectionalsurface of line

<Solder Heat Resistance>

Cured coatings of the photosensitive resin compositions of Examples 1 to6 and Comparative Examples 1 to 4 were each prepared according to theabove-mentioned method for the preparation of the substrate forevaluation. The film thickness was adjusted so that the film thicknessafter drying became 20±2 μm.

The coating was soaked into a solder bath at 260° C. for 10 seconds,which was repeated three times, and the peeling and discoloration of thecoating were confirmed by visual observation. As a result, no peeling ordiscoloration was confirmed in all of the substrates for evaluationprepared by using Examples 1 to 6 and Comparative Examples 1 to 4.

<Evaluation as Dry Film>

The photosensitive resin compositions of Example 2 and ComparativeExample 1 were each diluted with methyl ethyl ketone and applied to acarrier film. This was dried under heating to form a photosensitiveresin composition layer having a thickness of 20 μm, and the layer wasdried in a hot air drier at 80° C. for 30 minutes. Furthermore, a coverfilm was attached to the obtained coating to give a dry film. The coverfilm was thereafter peeled off, the obtained film was heat-laminated ona patterned copper foil substrate and then exposed in a similar mannerby using an exposure device comprising a metal halide lamp mountedthereon (manufactured by Orc Manufacturing Co., Ltd.). After theexposure, the carrier film was peeled off, and the substrate was curedby heating in a hot air drier at 150° C. for 60 minutes to prepare atest substrate. For the obtained test substrate having a cured coating,evaluation tests on the respective properties were conducted accordingto similar test methods and evaluation methods to those for theabove-mentioned compositions. The result was similar to the evaluationresult for Example 2 and Comparative Example 1 shown in Table 1.

1. A photosensitive resin composition, comprising: a perylene coloringagent; a coloring agent, which is in a complementary color relation withthe perylene coloring agent; a carboxyl group-comprising resin; acompound comprising two or more ethylenically unsaturated groups in amolecule; and a photopolymerization initiator.
 2. The photosensitiveresin composition of claim 1, wherein a dry coating of thephotosensitive resin composition having a thickness of from 18 to 22 μmhas a light absorbance of 0.5 or less at a wavelength in a range of from400 to 410 nm, and a cured product of the dry coating has an L* value of40 or less and an a* value and a b* value that are each independently ina range of from −5 to 5 in the CIE L*a*b* Color Scale.
 3. A dry film,comprising a coating obtained by a process comprising: applying thephotosensitive resin composition of claim 1 on a film, to obtain acoated film; and drying the coated film, thereby obtaining the dry film.4. A cured product, obtained by a process comprising: applying thephotosensitive resin composition of claim 1 on a substrate, to obtain acoated substrate; drying the coated substrate, to obtain a dry coatedsubstrate; and photo-curing the dry coated substrate by irradiating thedry coated substrate with an active energy ray, thereby obtaining thecured product.
 5. A printed wiring board comprising a pattern of a curedproduct obtained by a process comprising: applying the photosensitiveresin composition of claim 1 on a substrate, to obtain a coatedsubstrate; drying the coated substrate, to obtain a dry coatedsubstrate; and photo-curing the dry coated substrate by irradiating thedry coated substrate with an active energy ray, thereby obtaining thecured product.
 6. A cured product, obtained by a process comprising:applying the photosensitive resin composition of claim 1 on a film on asubstrate, to obtain a coated substrate; drying the coated substrate, toobtain a dry coated substrate; laminating the dry coated substrate, toobtain a laminated substrate; and photo-curing the laminated substrateby irradiating the laminated substrate with an active energy ray,thereby obtaining the cured product.
 7. A printed wiring boardcomprising a pattern of a cured product obtained by a processcomprising: applying the photosensitive resin composition of claim 1 ona film on a substrate, to obtain a coated substrate; drying the coatedsubstrate, to obtain a dry coated substrate; laminating the dry coatedsubstrate, to obtain a laminated substrate; photo-curing the dry coatedsubstrate by irradiating the dry coated substrate with an active energyray, thereby obtaining the cured product.
 8. The photosensitive resincomposition of claim 1, wherein a content of the perylene coloring agentin the photosensitive resin is from 0.01 to 8 parts by mass, based on100 parts by mass of the carboxyl group-comprising resin.
 9. Thephotosensitive resin composition of claim 1, wherein a content of theperylene coloring agent in the photosensitive resin is from 0.05 to 5parts by mass, based on 100 parts by mass of the carboxylgroup-comprising resin.
 10. The photosensitive resin composition ofclaim 1, wherein a content of the complementary coloring agent in thephotosensitive resin composition is from 0.01 to 8 parts by mass, basedon 100 parts by mass of the carboxyl group-comprising resin.
 11. Thephotosensitive resin composition of claim 1, wherein a content of thecomplementary coloring agent in the photosensitive resin composition isfrom 0.05 to 5 parts by mass, based on 100 parts by mass of the carboxylgroup-comprising resin.
 12. The photosensitive resin composition ofclaim 1, wherein the carboxyl group-comprising resin has an acid valuein a range of from 40 to 200 mg KOH/g.
 13. The photosensitive resincomposition of claim 1, wherein the carboxyl group-comprising resin hasan acid value in a range of from 45 to 120 mg KOH/g.
 14. Thephotosensitive resin composition of claim 1, wherein the carboxylgroup-comprising resin has a weight average molecular weight in a rangefrom 2,000 to 150,000.
 15. The photosensitive resin composition of claim1, wherein the carboxyl group-comprising resin has a weight averagemolecular weight in a range from 5,000 to 100,000.
 16. Thephotosensitive resin composition of claim 1, wherein a content of thecarboxyl group-comprising resin in the photosensitive resin compositionis 20 to 60 mass %, based on a total mass of the photosensitive resincomposition.
 17. The photosensitive resin composition of claim 1,wherein a content of the carboxyl group-comprising resin in thephotosensitive resin composition is 30 to 50 mass %, based on a totalmass of the photosensitive resin composition.
 18. The photosensitiveresin composition of claim 1, wherein the photopolymerization initiatoris at least one of an oxime ester polymerization initiator, anα-aminoacetophenone photopolymerization initiator, and anacylphosphineoxide photopolymerization initiator.